VEEPWATCH, PART 2: First, do no harm -- Our VP contenders

As part 2 of our Veepwatch series, we're unveiling our VP possibilities chart. See our video1 and also our full Veepwatch contenders list, both below. Who might Mitt Romney pick as his running mate? Did we miss anyone? If you think we did, pass along your suggested VP possibility along with a few short pluses and minuses to goodpolitics@virginia.edu2. Put “VP pick” in the subject line. We'll select the best three candidate suggestions and highlight them in next week's Crystal Ball; we'll alsosend the contributors a University of Virginia Center for Politics prize pack. -- The Editors

He's the ultimate Washington outsider, a rare national celebrity who is beloved by conservatives and who knows how to draw a crowd3. He would be the telegenic, young complement to the top man on the ticket, and, oh by the way, he made his name as one of the most famous figures from a key swing state. In other words, he's Mitt Romney's perfect running mate!

But, alas, former Florida Gators Heisman Trophy-winning quarterback and NFL sensation Tim Tebow is only 24 years old. One needs to be eligible to serve as president -- age 35 -- in order to be picked for the vice presidential slot.

With Romney having all but locked up the Republican nomination for president, national attention now turns to the Veepwatch. And more improbable names than Tebow will be bandied about before it's through.

In picking a running mate, Romney would be well advised to abide by the old Hippocratic Oath, “First, do no harm.” In a campaign sense, the barest minimum contribution a vice presidential selection can make to the ticket is not to torpedo the nominee's chances.

And yet, this political maxim is often violated. Four years ago, John McCain sought to excite a conservative base that long mistrusted him. Sarah Palin did that, but alienated much of the rest of the country. In 1984 Walter Mondale sought a similar spark from Geraldine Ferraro, but she was dogged by questions about her husband's finances. George McGovern said he was “1,000 percent” behind his initial pick in 1972, Missouri Sen. Thomas Eagleton, right before McGovern dumped Eagleton after stories emerged about his mental illness and electric shock therapy. In 1988, George H.W. Bush picked a youthful Dan Quayle to bridge the generational divide; Quayle eventually became a national punch line.

Beyond the campaign, a vice president also has to be loyal to the policies of the presidential candidate should he or she become president. Several picks have failed in this regard, too. Before there were Republicans who were derided as RINOs (Republican in Name Only), there was a WINO -- Whig in Name Only. After the sudden death of William Henry Harrison in 1841, John Tyler became president, and sabotaged the Whig Party program to the frustration of leading Whigs such as Henry Clay. Republican Abraham Lincoln's second vice president, Andrew Johnson, wasn't a RINO, because he was a Democrat. After Lincoln's assassination, Johnson infuriated Radical Republicans during the post-Civil War era. Theodore Roosevelt wound up on William McKinley's ticket largely because his enemies wanted to sidetrack his career in New York, where he was governor. Then McKinley was killed, catapulting Roosevelt into the presidency to the consternation of his enemies.

Perhaps the most important thing that Romney has to consider is that his pick must pass the litmus test of appearing able to step into the presidency at a moment's notice (after Palin, this will be especially critical to the evaluation of Romney's choice).

Topping our initial Veepwatch list is Sen. Rob Portman of Ohio. He would seem to be the definition of the “do-no-harm candidate,” although he also served in the Bush administration. No doubt the Obama campaign would try to exploit that association. The second name is a flashier candidate: Sen. Marco Rubio of Florida. Mentioned as a possible running mate essentially as soon as he won his Senate race in 2010, Rubio is a polished conservative who would reassure the Tea Party base and present a different (non-white) Republican face to the nation. But just as in the presidential race -- Rick Perry, for instance -- candidates who look ideal aren't always as perfect as they seem, and the press vetting is intense.

There are plenty more possibilities for Romney, and inevitably the Republican's campaign will review a couple dozen people, including some outside-the-box choices, before settling on the traditional short list. Until Romney announces his pick, the Veepwatch Kremlinology will continue.

By the way, there's no Democratic Veepwatch because we're not entertaining the (by now) outlandish idea of President Obama dumping Vice President Biden. Yes, we could make the case for Hillary Clinton; she is arguably a stronger choice than Biden and could potentially add electoral votes. But all that was true in 2008 as well, and changing back-up horses in the middle of the election year stream would be a media circus. Somehow it's hard to imagine Biden suffering this indignity in silence.